The number of equidistant oppositely charged ions in a sodium chloride crystal is:

Options

A. 8
B. 6
C. 4
D. 2

Answer

To solve the question regarding the number of equidistant oppositely charged ions in a sodium chloride (NaCl) crystal, we can follow these steps:

### Step 1: Understand the Structure of NaCl
Sodium chloride crystallizes in a face-centered cubic (FCC) lattice structure, where each sodium ion (Na⁺) is surrounded by six chloride ions (Cl⁻) and vice versa. This arrangement is known as the rock salt structure.

**Hint:** Recall that NaCl forms a cubic lattice where each ion is surrounded by ions of the opposite charge.

### Step 2: Determine the Coordination Number
In the rock salt structure, the coordination number refers to the number of nearest neighbors surrounding an ion. For Na⁺ ions, there are 6 Cl⁻ ions surrounding it, and for Cl⁻ ions, there are 6 Na⁺ ions surrounding it.

**Hint:** The coordination number indicates how many oppositely charged ions are directly adjacent to a given ion.

### Step 3: Conclusion
Since each Na⁺ ion is surrounded by 6 Cl⁻ ions at an equal distance, the number of equidistant oppositely charged ions in a sodium chloride crystal is 6.

**Final Answer:** The number of equidistant oppositely charged ions in a sodium chloride crystal is **6**.

### Summary of Steps:
1. Understand the structure of NaCl.
2. Determine the coordination number (6 for both Na⁺ and Cl⁻).
3. Conclude that the number of equidistant oppositely charged ions is 6.